Home » ASN News
Pakistan: Maintenance lapse preceded engine failure on ATR 42 that crashed two years ago
11 January 2019

Pakistani investigators say a maintenance lapse preceded an engine failure that led to the accident of an ATR 42 in 2016.

On December 7, 2016, Pakistan International Airlines flight 661, an ATR 42-500, was destroyed after impacting a hillside near Havelian, Pakistan. All 47 on board were killed.
The investigation board now issued two interim safety recommendations, stating that:

(a) Sequence of events was initiated with dislodging of one blade of power turbine Stage-1 (PT-1), inside engine number one (left-side engine) due to fatigue.
(b) This dislodging of one blade resulted in in-flight engine shut down and it contributed towards erratic/abnormal behavior of engine number one propeller.
(c) According to Service Bulletin these turbine blades were to be changed after completion of 10,000 hours on immediate next maintenance opportunity. The said engine was under maintenance on November 11, 2016, at that time those blades had completed 10004.1 hour (due for change). This activity should have been undertaken at that time but it was missed out by the concerned.
(d) Aircraft flew approximately ninety-three hours after the said maintenance activity before it crashed on December 7, 2016.
(e) Missing out of such an activity highlights a lapse on the part of PIA (maintenance and quality assurance) as well as a possible in-adequacy/lack of oversight by Pakistan CAA.

The following recommendations were issued:
(a) PIA is to ensure immediate implementation of said Service Bulletin in letter and spirit on the entire fleet of ATR aircraft, undertake an audit of the related areas of maintenance practices, ascertain root cause(s) for the said lapse, and adopt appropriate corrective measures to avoid recurrence.
(b) Pakistan CAA is to evaluate its oversight mechanism for its adequacy to discover lapses and intervene in a proactive manner, ascertain shortfall(s) and undertake necessary improvements.

The investigation is still ongoing.

Tags: ,